1. Field of the Invention
The present invention relates generally to a hard disk drive, and more particularly to a method and apparatus for cleaning air in the hard disk drive, in which the air in the periphery of the disk can be gathered to the center of the rotor and then discharged below.
2. Description of the Prior Art
In general, a spindle motor used in a hard disk drive or a magnetic recording and reading apparatus, as will be seen in FIG. 1, includes a number of disks a2, a spacer a3 interposed between the disks, and a clamp a4 for locking the uppermost portion of the disks and the upper surface of the rotor a1, as will be shown in FIG. 3, in which the upper and lower ends of the rotating shaft a5 are journalled to a housing a6 by bearings a7.
Because the above disks operate in very close proximity with a head, for example with a gap of about 0.2 .mu.m, they should prevent the dust from coming in. Accordingly, the periphery of the disks is called a cleaning area in which clean air should be maintained.
For example, an outer casing a8 is provided with an air filter a9 to remove dust or fine powdery substances contained in the air and to take in only clean air. The upper motor bearing is provided with a seal apparatus such as a labyrinth seal a10 or a magnetic fluid seal to prevent bearing grease or the like from scattering toward the disks.
In another prior art structure as shown in FIG. 2 the disk clamp b1 has only a clamping function. With the structure having an air filter b3 provided to casing b2, air swirls caused by the rotating disk b4 disperses the air radially and outwardly by centrifugal force such that the dust in the air tends to leak out toward the disk b4.
In addition, if the seal apparatus, i.e., seal a10, rotates faster than a predetermined spinning speed or is used for a long time, the liquid magnet may be scattered. In addition, the seal is very expensive, and due to a number of components that require assembly it is difficult to manufacture, thereby curtailing the productivity.